If you want to distinguish Zabbix the greatest inclusion you could add is that you can integrate into the frontend the R statistical package.

http://www.r-project.org/

With this you can immediately support more graph types than any other monitoring vendor on the planet.

It will take you more time to add a single new graph type than to convert the graphing to R and display it.

And once the graphs are done in R, than you can pull in R graph types in minutes. Including complex animated graphs to play back metric interaction over a time window.